Pain
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The relationship between temporo-spatial stimulus parameters and evoked pain intensity as well as duration was examined in patients with peripheral neuropathy and brush-evoked allodynia, i.e. dynamic mechanical allodynia. Brush-evoked allodynia was induced in the innervation territory of the lesioned nervous structure in 18 patients by lightly stroking different distances of the skin (20, 40, 60 mm) two or four times with brushes of different widths (4, 8, 16 mm). Pain intensity and duration of brush-evoked allodynia was recorded using a computerized visual analogue scale. ⋯ Significantly increased duration of aftersensation was demonstrated only following increased brushing length (P<0.008). The most commonly used sensory-discriminative pain descriptors were pricking, burning and sore and for the affective descriptors, annoying and troublesome. This is the first study demonstrating a relationship between evoked pain and some temporo-spatial stimulus parameters during brush-evoked allodynia.
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The alpha2A and alpha2C adrenergic receptor (AR) subtypes mediate antinociception when activated by the endogenous ligand norepinephrine. These receptors also produce antinociceptive synergy when activated concurrently with opioid receptor activation. The involvement of the opioid receptors in the mechanisms governing transcutaneous electrical nerve stimulation (TENS) has been well described. ⋯ The alpha2 adrenergic receptor selective antagonist, SK&F 86466, reversed TENS-mediated antihyperalgesia when delivered intra-articularly, but not when delivered intrathecally or intracerebroventricularly. These data suggest that peripheral alpha2 ARs contribute, in part, to TENS antihyperalgesia. This pharmacodynamic response is consistent with previous anatomical observations that alpha2A ARs are expressed on primary afferent neurons and macrophages near injured tissue.
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Little is known about how other than cancer pain related issues are represented in medical education. A standardised questionnaire was mailed to all medical students who graduated from the five Finnish medical schools in 2001. A total of 387 students received the questionnaire and 41% responded. ⋯ The clinical problems were excellently solved. In conclusion, the IASP curriculum is well covered in the present programmes in the Finnish medical faculties. However, the quality and the methods of teaching still need improvement.
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Comparative Study
The ontogeny of neuropathic pain: postnatal onset of mechanical allodynia in rat spared nerve injury (SNI) and chronic constriction injury (CCI) models.
Neuropathic pain is known to occur in children but remains poorly understood and treated. The aim here was to establish a model of neuropathic pain in neonatal and young rodents. In the adult the spared nerve injury (SNI) model produced robust mechanical allodynia measured as a fall in cutaneous sensory threshold to 16% of controls, within one postoperative day and lasting at least 28 days. ⋯ A similar lack of neuropathic pain behaviour in younger animals was observed using the chronic constriction injury (CCI) model, which produced a clear allodynia in adult rats but no change in hindpaw sensitivity when performed at 10 days of age. Mechanical allodynia can be evoked in very young animals with inflammatory pain, so this developmental profile is selective for peripheral neuropathic pain and suggests a remarkable ability in young animals to compensate for the sensory consequences of nerve injury. The results are consistent with human neonatal responses to nerve injury; further study of underlying mechanisms are likely to yield important information about the pathogenesis and treatment of neuropathic pain.